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It sounds kind of stupid and obvious to say that the brain and its workings are very complicated. But let's start with that simple assumption.

And you might think that neuroscience (the science of the brain) would have hardly any practical uses at all. But you would be wrong.

According to the Journal Psychology Today, the fast-food industry uses neuroscience. In fact, the article in Psychology Today claims that "many recent neuroscience discoveries about food's effects on our brains, and how we make decisions about food, are actually gold-standard trade secrets from super chains such as McDonald's".

The article, with the catchy title of 'Seven things McDonald's Knows About Your Brain', lifts the lid on the neuroscience that the fast-food chains use to make us buy unhealthy food, even when we're not hungry.

The first neuroscience discovery they use is that under certain circumstances, sugar can be addictive. That's right, plain old sugar can give you, or at least some laboratory rats, all the hallmarks of addiction — bingeing, withdrawal and craving.

The scientists starved the rats for 12 hours, then for a brief time let them have as much sugar and water as they wanted, and then starved them again, and then gave them as much sugar and water as they wanted, and kept on repeating the cycle.

At first, the rats took only as much sugar and water as their bodies needed. But pretty soon, they were taking twice as much as they needed.

Then the scientists gave the rats a drug that blocked the pleasurable effects of addictive drugs in the brain. Suddenly, the rats were getting the sugar, but they weren't getting their beloved high.

They immediately began showing absolutely typical signs of drug withdrawal — tremors in the body, chattering of the teeth, and so on.

So in rats, and almost certainly in humans, sugar can be addictive.

In McDonald's and other fast-food chains, practically everything contains sugar. Not just the drinks and the ketchup, but even the bread in the hamburger buns, and wait for it, the fries.

But what about the new 'healthy' stuff, like the fruit smoothies? Well, it turns out that they actually have more sugar per drink than a cup of cola.

The second neuroscience discovery used by the fast-food companies relates to the concepts of impulse control and convenience.

Now, we're all different. Some of us are really good at resisting temptation, but others among us cave in easily. One part of your brain, the prefrontal cortex, helps deal with impulse control.

But the reward centre in your brain, the nucleus accumbens, can undermine and interfere with your prefrontal cortex.

If the temptation is continually in front of you, the reward centre (which loves the quick fix) might win, and you'll end up eating high-sugar, high-fat fast food again. Not the best and healthiest long-term decision.

The way that the fast-food industry uses their knowledge of this impulse control is the magic word 'convenience'.

Just a few minutes of driving around any capital city will get you a fast-food outlet. That's convenient!

With regard to fast food, some of us have only a certain amount of impulse control.

In the same way, every time that large deliveries of cocaine and heroin hit a capital city, drug use and overdoses go through the ceiling. Yep, make it convenient, and they will come.

The neuroscience gets quite complicated, especially when you start dealing with the neurotransmitter called dopamine. And it gets even more complicated when you realize that there are at least five different types of dopamine receptors on your cells.

But one fairly straightforward and robust finding seems to be that if you have fewer dopamine2 (or D2) receptors, you are more overweight.

The third neuroscience factor used by the fast food companies is speed of delivery.

If you suck on a burning cigarette, within 20 seconds the drug nicotine is affecting your brain cells.

That speed of delivery is part of what makes nicotine such an addictive drug. And the same goes for heroin. The closer the timing between the stimulus (such as nicotine or heroin) and the reward that it delivers to the brain, the more addictive that stimulus can be.

Now, if you're cooking food at home, it can easily take a whole three minutes just to get the frypan hot. But with fast food, within three minutes of placing your order, you be sinking your teeth into that sugar-charged hamburger bun.

That speed of delivery enhances the addictive potential of fast food.

At this stage, we are only halfway through the neuroscience of fast food. So tune in next time, for another bite.

Comments (8)

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AnonymousOpinion :

31 Aug 2011 1:45:46pm

But please sir, I can have that pot or two heated and a meal of, say, stir fry with sweet and sour and rice ready to chow down on inside 20 minutes.Or I can open the cereal packet and munch inside 30 seconds.There are no "fast food" shops that can get their wares into me inside the 20 minutes it would take me to walk, ride or drive to their shop, queue, pay, and wait for the chef to deliver.Maybe the neuro theory applies when the stimulus is the golden arches or the big burger photo - otherwise the sugar jonesing would have to have been conditioned via getting the sugar fix at a particular shop for a fairly consistent training period.Which I suppose advertising takes care of.

James Hermans :

07 Sep 2011 1:07:21pm

It's great to see this information finally making its way into the public, but much more needs to be done.

While I am all for personal responsibility and against the nanny state controlling what we watch and eat. Something needs to happen to make the pedlars of these harmful products own up to their societal responsibilities and justify their profits!

jenniwren :

27 Oct 2011 6:32:44pm

I watched your interview on The Drum last night and I was impressed with you arguement reguarding IQ and the difference in choice the people with less or more than 100IQ can make. I have been thinking about this for quite a while now and the arguement I get is "well you can function very well on 100IQ". It was gratifying to see you put out the argument. I wonder if you have also looked at the arguments for fructose also being used in food as sugar since the 1980's.I think the idea of "choice" and blaming the individual for any thing from obessity to bad government is highly spurious when you consider that we are always being bombarded with messages via advertising against our better interests in the name of "thats Business"I am not sure exactly how much choice we actually have have.Cheers Jennifer

Trufflenut :

28 Oct 2011 12:04:37pm

I also saw you on teh Drum and I've never seen someone silence a panel as much as your jaw dropping point about people's IQ. Masterful. My theory on obesity is that your brain looks for a set amount of vitamins and minerals every day and if you send it down along with excess amount of fat, sugar etc, your body just has to deal with it. I defy anyone to overeat if all they consume is healthy, nutritious low calorie fresh food! I'm experimenting on myself and never has losing weight been easier. And believe me, that's saying something, the number of "diets" I've been on. Well done Dr Karl.